1. Technical Field
The present invention relates in general to an improved radio frequency component and a method of making it. The invention more particularly relates to a radio frequency component, which is environmentally protected and which is thus more reliable and dependable in its operation.
2. Background Art
There have been many different types and kinds of surface mounted radio frequency components which interact with signals having frequencies between approximately one kilohertz and approximately 26 gigahertz. Such radio frequency components require the use of circuit boards having a number of traces thereon to cooperate with components having electronic devices on a carrier. A pair of input/output pads or contact areas located on the underside of the surface of the carrier member are connected to the electronic devices to provide an external connection point to the circuit board traces by suitable techniques such as soldering.
In order to facilitate the arrangement of the radio frequency components on the circuit board in a more compact manner, a method and device shown in U.S. Pat. No. 5,444,187 was invented to facilitate the closely spaced surface mounting of the components on the circuit board. The U.S. Pat. No. 5,444,187 is incorporated herein by reference. Such a technique reduced greatly the need for customizing the radio frequency components and increased the component density on the circuit board. Additionally, the circuit board layout design requirements were greatly simplified.
As disclosed in U.S. Pat. No. 5,444,187, the method briefly relates to the use of radio frequency components having input/output contact points or areas at corners of the underside of the component. This arrangement permits the component to be positioned relative to a pair of circuit board traces for enabling an electrical connection thereto in a range of angular dispositions, thereby facilitating greatly the increase of component density and enabled greater freedom in arranging advantageously the components on the circuit board without requiring expensive customization of the components.
While such a patented technique has proven to be highly successful, there still remains the draw back associated with all surface mounted radio frequency components relating to inherent unreliability due to moisture encroachment and RF shielding (prevention of RF interference with other adjacent components. In this regard, radio frequency components including electronic devices such as filters are adversely affected by moisture caused by condensation from temperature variations, or from the use of the radio frequency component in outside environments. Also, moisture encroachment can be caused by spraying solutions such as cleaning agents, solvents or conformal coatings onto the carrier.
Such unwanted moisture encroachment can cause short circuiting or other undesirable affects such as de-tuning a filter device. Additionally, other components such as capacitors and inductors do not perform satisfactorily when wet. Additionally, other environmental problems such as dust particles or the like infiltrating the surface mounted radio frequency component can cause undesirable and unwanted affects as well. Therefore, it would be highly desirable to have a new and improved radio frequency component, which performs more satisfactorily and reliably and is protected against unwanted environmental problems.